Get Oracle 1Z0-084 Exam Dumps

Answer : C, D

Big Table caching is a feature that allows frequently accessed large tables to be cached in memory to improve I/O performance. From the parameter settings provided, Big Table caching is not occurring because DB_BIG_TABLE_CACHE_PERCENT_TARGET is set to 10, which is the minimum threshold for enabling the feature, but the size of the cache is too small for the big tables to be effectively cached.

To enable Big Table caching, one of the following actions could be taken:

C (Correct): Increasing DB_BIG_TABLE_CACHE_PERCENT_TARGET to at least 25. This action would allocate a larger percentage of the buffer cache for storing big tables, which could allow for caching large tables and thus improve I/O performance.

D (Correct): Increasing DB_CACHE_SIZE to 1G. Since the size of the buffer cache is a determining factor for how much data can be cached, increasing this parameter would provide more memory space for big tables to be cached.

Options A, B, E, and F will not enable Big Table caching because:

A: Increasing DB_BIG_TABLE_CACHE_PERCENT_TARGET to 50 without adjusting the overall size of the cache might still not be sufficient if the DB_CACHE_SIZE is not large enough to hold the big tables.

B: Setting DB_KEEP_CACHE_SIZE to at least 50M only specifies a separate buffer pool for objects with the KEEP cache attribute and does not affect Big Table caching.

E: and F: Changing the PARALLEL_DEGREE_POLICY to ADAPTIVE or AUTO influences the behavior of parallel execution but does not directly enable or influence Big Table caching.

Oracle Database Performance Tuning Guide: Big Table Caching

Oracle Database Reference: DB_BIG_TABLE_CACHE_PERCENT_TARGET

Oracle Database Reference: DB_CACHE_SIZE

Answer : A, E

To investigate the cause of the ORA-04036 error, which indicates that PGA memory usage exceeds the PGA_AGGREGATE_LIMIT, the appropriate views to consult are DBA_HIST_ACTIVE_SESS_HISTORY and DBA_HIST_PROCESS_MEM_SUMMARY.

DBA_HIST_ACTIVE_SESS_HISTORY: This view provides historical information about active sessions in the database. It includes details about the SQL executed, the execution context, and the resources consumed by each session. By examining this view, you can identify the specific sessions and SQL queries that were active and potentially consuming excessive PGA memory around the time the ORA-04036 error occurred.

DBA_HIST_PROCESS_MEM_SUMMARY: This view contains historical summaries of memory usage by processes. It can help in identifying the processes that were consuming a significant amount of PGA memory, leading to the ORA-04036 error. This view provides aggregated memory usage information over time, making it easier to pinpoint the processes responsible for high PGA memory consumption.

Together, these views offer a comprehensive overview of the memory usage patterns and specific queries or processes that might have contributed to exceeding the PGA_AGGREGATE_LIMIT, resulting in the ORA-04036 error.

Oracle Database Reference: DBA_HIST_ACTIVE_SESS_HISTORY

Oracle Database Reference: DBA_HIST_PROCESS_MEM_SUMMARY

Oracle Database Performance Tuning Guide: Managing Memory

Answer : D

In Oracle Database, the V$SESSION_LONGOPS view provides insights into various operations within the database that are expected to take more than six seconds to complete. These include operations related to RMAN (Recovery Manager), such as database duplication tasks. This view displays information about the progress of these long-running operations, including the start time, elapsed time, and estimated time to completion.

When an RMAN session is performing a database duplication and is observed to be slower than usual, checking the V$SESSION_LONGOPS view can give an approximation of when the RMAN operation might complete. This view includes fields like TIME_REMAINING and ELAPSED_SECONDS that help in estimating the completion time of the operation based on its current progress.

Oracle Database Reference: V$SESSION_LONGOPS

Oracle Database Backup and Recovery User's Guide: Monitoring RMAN Jobs

Answer : A, C, F

Server-generated alerts in Oracle Database are designed to notify DBAs and other administrators about issues within the database environment. These alerts can be triggered by a variety of conditions, including threshold-based metrics and specific events such as ORA- error messages. Here's how these options align with the statements provided:

A (True): Server-generated alerts are indeed notifications from the Oracle Database Server that highlight existing or impending issues. These alerts are part of Oracle's proactive management capabilities, designed to inform administrators about potential problems before they escalate.

C (True): These alerts are logged in the alert log of the Oracle Database. The alert log is a crucial diagnostic tool that records major events and changes in the database, including server-generated alerts. This log is often the first place DBAs look when troubleshooting database issues.

F (True): Server-generated alerts may include suggestions for correcting identified problems. Oracle Database often provides actionable advice within these alerts to assist in resolving issues more efficiently. These suggestions can range from adjusting configuration parameters to performing specific maintenance tasks.

Options B, D, and E do not accurately describe server-generated alerts:

B (False): While the statement might have been true in some contexts, Oracle's server-generated alerts often include corrective suggestions, making this statement incorrect.

D (False): Server-generated alerts can be viewed from various interfaces, not just the Cloud Control Database home page. They are accessible through Enterprise Manager, SQL Developer, and directly within the database alert log, among other tools.

E (False): While it's true that threshold settings for some alerts can be modified, the method specified, using DBMS_SERVER_ALERT, is not correct. Threshold settings are typically adjusted through Enterprise Manager or by modifying specific initialization parameters directly.

Oracle Database Documentation: Oracle Database 19c: Performance Management and Tuning

Oracle Base: Alert Log and Trace Files

Oracle Support: Understanding and Managing Server-Generated Alerts

Answer : B

The SHRINK SPACE operation compacts the table, which can reduce fragmentation and thus improve performance for sequential reads of the table. This operation could improve full table scans, which are typically associated with db file sequential read wait events.

Oracle Database Administrator's Guide, 19c